Results & Discussion

The plot based on total beta diversity of aquatic invertebrate beta diversity and total trout abundance shows that aquatic invertebrate indeed is positively correlated with trout abundance, that is, if Burnt Timber is excluded (Figure.4). Excluding Burnt Timber not only leads to a higher level of correlation, but also to a slope that is 2.48 times greater than the one that does include it.

The plot based on replacement and total trout abundance highly resembles the one based on total beta diversity and total trout abundance above, although it has both a higher positive slope and noteworthy a higher adjusted R²-value (Figure.8). Again like with total beta diversity, when Burnt Timber is not included the correlation becomes much stronger. Furthermore, apart from having a much higher degree of correlation when excluding Burnt Timber, it also results in a slope that is 2.45 times greater than the one that does include it.

No significant correlation was found between either alpha diversity and trout abundance (Figure.18, Figure.19) or invertebrate abundance and trout abundance (Figure.20). This likely disproves my hypothesis and could be due to different factors that could include the trout in these streams simply not being as dependent on aquatic invertebrates as expected, or it could be the case that the preferred aquatic invertebrate taxa

There also was no significant correlation found between species specific trout abundances and total beta diversity or replacement (Figure.5, Figure.6, Figure.7, Figure.9, Figure.10, Figure.11). This likely disproves my hypothesis and could be due to different factors that could include some species simply not being present

Furthermore, no significant correlation was found between nestedness and total trout abundance nor with any trout species specific abundance (Figure.12, Figure.13, Figure.14, Figure.15). It is worth noting however that nestedness in these streams only make up a relatively small percentage of total beta diversity (Figure.3), meaning that in streams where nestedness plays a bigger role, there is a chance the correlation could be stronger. Interestingly, while nestedness was negatively correlated with total trout abundance, bull trout abundance and brown trout abundance as expected, this was not the case with brook trout which had a positive relationship.

Both total beta diversity and replacement have positive relationships with trout abundance (Figure.4, Figure.8). However, while both are significant, as long as Burnt Timber is not taken into account, replacement has by far the highest adjusted R² value, suggesting that it is more directly correlated with trout abundance as well as being highly significant even when Burnt Timber is included. As a result, this suggests that replacement would be the better option to assess habitat quality for trout than total beta diversity as long as Burnt Timber does turn out to be a true outlier.

In conclusion: total beta diversity of aquatic invertebrates is positively correlated with trout abundance with 98% confidence at an adjusted R² of 0.6171 and replacement of aquatic invertebrates is positively correlated with trout abundance with 99% confidence at an adjusted R² of 0.7743, as long as Burnt Timber is in fact an outlier. As such both total beta diversity and replacement of aquatic invertebrates could potentially be used in habitat assessment for management and restoration projects although replacement would be preferred as it is more highly correlated with trout abundance.

However, more sampling is needed to determine if Burnt Timber is in fact a true outlier and therefore wether the results are significant.